Formal inversion of laterally heterogeneous velocity structure from P-wave polarization data

We use seismic wave polarization directions to determine three-dimensional seismic velocity structure. Linearized inverse theory is used. The data kernel, which represents the change in polarization direction at the receiver due to perturbations in the velocity structure is computed by a variational technique that employs ray integrals. Three-dimensional tests of the method using synthetic data demonstrate its accuracy and usefulness in the presence of noise.